直缝埋弧焊管焊偏测量方法探讨

分析了焊偏的定义,对直缝埋弧焊管焊偏量的测量方法及其优缺点进行了比较,列举了国内外相关标准对焊偏量的相关要求,并进行分析。结果表明:API标准和石油行业标准中对焊偏定义只是粗略的概括,其测量方法并不明确;焊趾中心线法、焊道弧顶点距离法、焊道中脊线法及X射线检验法各有优缺点,但都难以准确反映实际偏移量,建议采用焊道熔合区中心线法,此法较为唯一和准确;在管道外径较大的情况下,建议使用外焊道焊趾连线或壁厚中心连线为钢管表面切线平行线,使得焊道熔合区中心线法更具可操作性和唯一性,建议GB/T 9711—2011中对焊偏量的测量方法采用焊道熔合区中心线法;国内直缝埋弧焊管焊偏量的限定标准是在参考国外同类型标准的基础上制定的,在重大工程的应用中偏于严格。

Determining Method of Weld Misalignment of Longitudinal Submerged Arc Welding Steel Pipe

The definition of welding misalignment was analyzed, the advantages and disadvantages of determining method of longitudinal submerged arc welding steel pipe weld misalignment were compared. The relevant requirements for welding misalignment in the relevant standards at home and abroad were listed and analyzed. The results showed that the definition of welding misalignment in API standard and the oil industry standard is a rough summary and the method of measurement is not clear. It has the advantages and disadvantages of the determining method of weld misalignment by using the weld toe center line method, the weld arc vertex distance method, the ridge line bead method and the X-ray test method, and they are difficult to accurately reflect the actual offset. It is recommended that using the weld fusion zone center line method to determine weld misalignment because it is more unique and accurate. In the case of larger diameter of pipe, the outside weld toe line or the center line of the wall thickness is recommended to be the parallel line of the steel pipe tangent line, and it would be more operability and uniqueness for the weld fusion zone center line method. The weld fusion zone center line method is recommended to determine weld misalignment for GB/T 9711—2011. The limited standard of welding misalignment in our nation is formulated on the basis of foreign standards of the same type and it is stricter in abroad in the application of major engineering projects.